<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .demo {
      background-color: antiquewhite;
    }
  </style>
</head>

<body>
  <button id="btn">点击创建输入框</button>
  <script type="text/javascript">
    const btn = document.getElementById('btn')
    btn.onclick = () => {
      const input = document.createElement('input')

      input.className = 'demo'
      input.value = 99
      input.onclick = () => { alert(1) }

      document.body.appendChild(input)

      input.focus()
      input.parentElement.style.backgroundColor = 'skyblue'
      // console.log(input.parentElement);
    }
  </script>
</body>

</html>